DSpace Community:http://hdl.handle.net/2328/2961
Tue, 03 Mar 2015 22:48:16 GMT2015-03-03T22:48:16ZA dynamical (e,2e) investigation of the structurally related cyclic ethers tetrahydrofuran, tetrahydropyran, and 1,4-dioxanehttp://hdl.handle.net/2328/26887
Title: A dynamical (e,2e) investigation of the structurally related cyclic ethers tetrahydrofuran, tetrahydropyran, and 1,4-dioxane
Authors: Builth-Williams, J D; Bellm, Susan; Chiari, Luca; Thorn, Penny Anne; Jones, Darryl Bruce; Chaluvadi, Hari; Madison, D H; Ning, C G; Lohmann, B; da Silva, G B; Brunger, Michael James
Abstract: Triple differential cross section measurements for the electron-impact ionization of the highest occupied molecular orbitals of tetrahydropyran and 1,4-dioxane are presented. For each molecule, experimental measurements were performed using the (e,2e) technique in asymmetric coplanar kinematics with an incident electron energy of 250 eV and an ejected electron energy of 20 eV. With the scattered electrons being detected at −5°, the angular distributions of the ejected electrons in the binary and recoil regions were observed. These measurements are compared with calculations performed within the molecular 3-body distorted wave model. Here, reasonable agreement was observed between the theoretical model and the experimental measurements. These measurements are compared with results from a recent study on tetrahydrofuran in order to evaluate the influence of structure on the dynamics of the ionization process across this series of cyclic ethers.Wed, 17 Jul 2013 00:00:00 GMThttp://hdl.handle.net/2328/268872013-07-17T00:00:00ZA joint theoretical and experimental study for elastic electron scattering from 1,4-dioxanehttp://hdl.handle.net/2328/26835
Title: A joint theoretical and experimental study for elastic electron scattering from 1,4-dioxane
Authors: Palihawadana, Prasanga; Sullivan, James; Buckman, Stephen J; Masin, Zdenek; Gorfinkiel, Jimena D; Blanco, Francisco; Garcia, Gustavo; Brunger, Michael James
Abstract: We present results of measurements and calculations of elastic electron scattering from 1,4-dioxane in the energy range of 0–1000 eV. Absolute differential and integral elastic cross sections have been measured using a crossed electron-molecule beam spectrometer and the relative flow technique, at four energies in the 10–30 eV range and for scattered electrons in the angular range 20°–129°. The measured cross sections are compared with results from R-matrix computations, at the static exchange plus polarization level, calculated at energies between 0–20 eV, and with calculations employing the independent atom model with the screening corrected additivity rule (IAM-SCAR). Those latter computations were conducted at energies between 1 and 1000 eV. Agreement between the measured and R-matrix cross sections was typically found to be good at all common energies, whereas agreement with IAM-SCAR was satisfactory only at 30 eV. To the best of our knowledge, the present results are the first absolute data to be published in the literature for this scattering system.Tue, 02 Jul 2013 00:00:00 GMThttp://hdl.handle.net/2328/268352013-07-02T00:00:00ZCross sections for elastic scattering of electrons by CF3Cl, CF2Cl2, and CFCl3http://hdl.handle.net/2328/26823
Title: Cross sections for elastic scattering of electrons by CF3Cl, CF2Cl2, and CFCl3
Authors: Hoshino, M; Horie, M; Kato, H; Blanco, Francisco; Garcia, Gustavo; Limao-Vieira, P; Sullivan, James; Brunger, Michael James; Tanaka, Hiroshi
Abstract: Differential, integral, and momentum transfer cross sections have been determined for the elastic scattering of electrons from the molecules CF3Cl, CF2Cl2, and CFCl3.With the help of a crossed electron beam–molecular beam apparatus using the relative flow technique, the ratios of the elastic differential cross sections (DCSs) of CF3Cl, CF2Cl2, and CFCl3 to those of He were measured in the energy region from 1.5 to 100 eV and at scattering angles in the range 15° to 130°. From those ratios, the absolute DCSs were determined by utilizing the known DCS of He. For CF3Cl and CF2Cl2, at the common energies of measurement, we find generally good agreement with the results from the independent experiments of Mann and Linder [J. Phys. B 25, 1621 (1992)10.1088/0953-4075/25/7/030; Mann and Linder J. Phys. B 25, 1633 (1992)10.1088/0953-4075/25/7/031]. In addition, as a result of progressively substituting a Cl-atom, undulations in the angular distributions have been found to vary in a largely systematic manner in going from CF4 to CF3Cl to CF2Cl2 to CFCl3 and to CCl4. These observed features suggest that the elastic scattering process is, in an independently additive manner, dominated by the atomic-Cl atoms of the molecules. The present independent atom method calculation typically supports the experimental evidence, within the screened additivity rule formulation, for each species and for energies greater than about 10–20 eV. Integral elastic and momentum transfer cross sections were also derived from the measured DCSs, and are compared to the other available theoretical and experimental results. The elastic integral cross sections are also evaluated as a part of their contribution to the total cross section.Tue, 04 Jun 2013 00:00:00 GMThttp://hdl.handle.net/2328/268232013-06-04T00:00:00ZSpectroscopic observation of gold-dicarbide: photodetachment and velocity map imaging of the AuC2 anionhttp://hdl.handle.net/2328/26786
Title: Spectroscopic observation of gold-dicarbide: photodetachment and velocity map imaging of the AuC2 anion
Authors: Visser, Bradley; Addicoat, Matthew A; Gascooke, Jason; Lawrance, Warren Donald; Metha, Gregory Francis
Abstract: Photoelectron spectra following photodetachment of the gold dicarbide anion, AuC−
2 , have been
recorded using the velocity map imaging technique at several excitation wavelengths. The binding
energy spectra show well-defined vibrational structure which, with the aid of computational calculations
and Franck-Condon simulations, was assigned to a progression in the Au–C stretching mode,
ν3. The experimental data indicate that the features in the spectrum correspond to a 2A ←3A transition,
involving states which we calculate to have bond angles ∼147◦ but with a low barrier to
linearity.Tue, 07 May 2013 00:00:00 GMThttp://hdl.handle.net/2328/267862013-05-07T00:00:00Z